Hesitation and cut-off when accelerating - 2007 50HP two stoke

[nuthouseinva]

Symptom #1:
The last couple times I've taken my skiff out I noticed the motor would hesitate for a second after giving it throttle when taking off to get the boat on plane.
It seems like the motor takes a second to recognize the throttle position and then it kicks in. A little unnerving sometimes because there is a little delay and then the boat accelerates all of a sudden.
It doesn't seem to do it every time but a good majority. I've tried varying acceleration and I believe the issue remains except for maybe really slow acceleration.

Symptom #2:
This only happened on the last trip. I was powerloading the boat onto the trailer. Was using minimal acceleration to get on the trailer and line everything up and then increased throttle to push the boat up the bunks. When increasing the throttle the motor shut-off and I never made it up the bunks. I retried several more times and same thing happened. Finally made it up the trailer by only getting a little more of a head start and didn't have to give it the little extra gas. On one of those attempts it took me a couple cranks to get the motor restarted.

All else runs and operates great from what I can tell. I've put fresh fuel in almost every trip and use fuel stabilizer with every fill up.

My suspicion and plan:
I bought this boat in 2010 and the previous owner has taken real good care of it. I have not replaced the fuel/water separation filter since then so I plan to try that first. And maybe look at the inline fuel filter (I suspect it has one under the cowl). My first guess is a fuel issue.?
I'm not completely mechanically ignorant but I've never troubleshooted outboard issues. Any other suggestions for troubleshooting?

Thanks in advance for your help.

[99yam40]

you can check to make sure timing is in spec at idle and when advancing the throttle, but my guess is the carbs need a good cleaning and then follow the steps in service manual to link and sync the carbs

[nuthouseinva]

Fuel filter inspection.

I replaced the fuel water filter and ran motor on muffs. Seem to run good. normal for muffs.

Moved on to the fuel filter. That little sucker is tucked in there. Finally managed to remove and inspect. didn't see any debris which was good but it does have a good bit of discoloration and residue/varnish buildup. I will be replacing the filter element. Check out the pic. Is this normal?


I also drained the bowls of the top two carburetors. Couldn't get to the bottom one. Need a small universal joint or something? Any help there?

[nuthouseinva]

back to top.

[nuthouseinva]

Bumping to top. Hoping someone can review the filter photo I added.

[rodbolt17]

its a screen.
what do you want us to say?
spray it off and fix the fuel issue.
your describing a weak/defective fuel pump.

[liliepad1]

filter is old but fine . Sounds like leaking lift Pump or maybe its time for a carb job . never mind that thing is really varnished up time to clean them carbs

[nuthouseinva]

More testing

Finally got to run it after replacing the fuel/water separator and internal fuel screen/filter. Ran good on the muffs.
Took it to the river. In gear, it bogs down and tries to cut off at 1500 rpm. Not much acceleration at all. seemed to rev okay in neutral. Ran strong. A little bumpy in neutral idle.

Frustrated. brought it home put it back on muffs. Starts to get spurratic (sp) at 3000 rpm in neutral and in gear.
Scratching head. I thought maybe a lower unit issue since it bogs down in gear but with the issue at 3000 rpm I'm thinking clogged jet?
isn't there a high flow jet in the carb?

Will probably have to take it to the shop. probably more than I'm capable of at this point. Arggg. I take good care of my fuel, add stabilizer and run it empty after every use. Should I still have problems with varnishing?

[nuthouseinva]

oh and pumping the bulb while it was bogging down did not make any difference in operation.

[99yam40]

have you tested anything like fuel pressure/vacuum to make sure there is not a problem with that.

Have you looked at the fuel pump like others have suggested?
Revving a motor in neutral is never the proper test for anything

The carbs are not that hard to clean and set with service manual

[nuthouseinva]

Not sure how to test the fuel pressure vacuum or fuel pump.
I've looked a little into the carb cleaning and looks doable but would probably take me a while with my minimal mechanical skills, tools, etc.
I just picked up a Seloc manual so i'll be doing some more reading.

[nuthouseinva]

Compression test was good. Timing check was good. #3/bottom carb was not getting fuel to the float bowl. All carbs were removed and cleaned, new carb kit installed. New plugs. Removed old fuel. Flushed lines and all filters with fresh fuel. Fresh fuel in tank. All is running good again.

[99yam40]

Good to hear you got it taken care of, and sounds like you did a good job on the whole system if you cleaned the tank too.

See there I told you the carbs are not that hard to do